Unless otherwise indicated herein, the materials described in this section are not prior art to the claims and are not admitted to be prior art by inclusion in this section.
In a typical market area, a wireless service provider may operate one or more radio access networks (RANs) each arranged to provide mobile stations with wireless communication service. Each such a RAN may include a number of base stations that radiate to define wireless coverage areas in which to serve mobile stations according to a radio access technology such as Orthogonal Frequency Division Multiple Access (OFDMA (e.g., Long Term Evolution (LTE) or Wireless Operability for Microwave Access (WiMAX)), Code Division Multiple Access (CDMA) (e.g., 1×RTT and 1×EV-DO), GSM, GPRS, UMTS, EDGE, iDEN, TDMA, AMPS, MMDS, WIFI, and BLUETOOTH, or others now known or later developed. In turn, each base station may be coupled with network infrastructure that provides connectivity with one or more transport networks, such as the public switched telephone network (PSTN) and/or the Internet for instance. With this arrangement, a mobile station within coverage of a RAN may engage in air interface communication with one or more base stations and may thereby communicate via the base station(s) with various remote network entities or with other mobile stations served by the base station(s) or by other base stations.
As a mobile station is served by one or more such RANs, various network entities may establish records of associated information, to facilitate billing or other functions. Each such record may include an identifier of the mobile station and a timestamp specifying the date and time of the underlying data. Further, some such records may include information specifying one or more coverage areas in which the mobile station is operating or that the mobile station detects, as well as information related to distance of the mobile station from various base stations or the like.
For instance, such records may specify cells and cell sectors (e.g., by cell ID and sector ID) serving the mobile station or detected by the mobile station, locations of the base stations providing those cells and cell sectors, round trip signal delays between the mobile station and various base stations when the mobile station is in particular cells and cell sectors, and signal strengths detected by the mobile station from various base stations when the mobile station is in particular cells and cell sectors. In practice, the mobile station may report some or all of this information while the mobile station is served by one or more RANs, and various network entities may add or supply other associated information. Serving nodes of various types, such as mobile switching centers (MSCs), radio network controllers (RNCs), and mobility management entities (MMEs), may then record this information, possibly in conjunction with other information, in records related to registration of the mobile station in various coverage areas, handoff of the mobile station between coverage areas, calls or other communications in which the mobile station engages, and so forth.
Further, from time to time, various network entities may use this and/or other information to determine and record the geographic location of mobile stations with varying degrees of granularity, to facilitate providing location-based services such as navigation guidance, delivery of location-based marketing information, or the like, or for other reasons.
For example, by referring to a record specifying that a mobile station was operating in coverage of a particular cell sector at a given time, a server could approximate and record the location of the mobile station at that time as being the location of the base station providing that cell sector, as being a predefined centroid of that cell sector, or the like. As another example, by referring to data specifying that a mobile station was operating in two or more particular cell sectors at a given time, a server could average such cell-sector based locations and/or could apply trilateration based on round-trip delay measurements and/or signal strength measurements, to compute a location of the mobile station with greater granularity.
As still another example, a server could determine the location of a mobile station with even greater granularity through use of the global positioning system (GPS) or the like. For instance, after roughly approximating the location of the mobile station in a manner such as one of those noted above, the server could instruct the mobile station to tune to satellites in the sky over that roughly approximated location and could then receive satellite signal measurements from the mobile station. The server may then use those signal measurements to conduct a trilateration process so as to more accurately determine the mobile station's location. Still further, in an assisted-GPS process, the server could use a combination of satellite signal measurements and round trip delay or other cellular coverage measurements to determine the mobile station's location more quickly and/or with possibly greater accuracy.
To provide a location-based service based on the location of a mobile station, a server may ascertain the location of the mobile station by applying one or more location determination processes such as these or otherwise by ascertaining the location of the mobile station determined through one or more location determination processes such as these. In the event multiple such location fixes are available using different location determination processes (such a location fix based on round trip delay measurements with respect to one RAN serving the mobile station, and a separate location fix based on round trip delay measurements with respect to another RAN serving the mobile station), the server could combine the location fixes together such as by averaging them to establish a representative mobile station location, and/or the server could select one of the available location fixes as a representative mobile station location. The server may then query a database to obtain information keyed to that mobile station and may deliver that location-based information to the mobile station or to another entity.